Abstract: Synchronous periodic vibration forces are induced when a magnetically suspended rotor rotates at high speed. For the purpose of removing vibration forces, namely autobalancing, a method attenuating both synchronous current and displacement stiffness force is used in some applications. But the low-pass characteristic of power amplifier which increases with rotational speed causes error of the compensation for position stiffness force and even reduces system stability. A method based on lead feedforward compensation is proposed to achieve high-precision autobalancing. A feedforward mechanism from synchronous component of position to current is set up to compensate displacement stiffness force, and the simplified inverse model of power amplifier is included in the feedforward channel to reject the low-pass characteristic. Simulations indicate it reduces synchronous force to 20% of that without lead correction. Experiments indicate it reduces synchronous vibration acceleration to 28% of that without lead correction.

Key words: Autobalancing, Feedforward compensation, Lead correction, Magnetic bearing, Drops、Fluid volume model、Numerical simulation、PID